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Soil that is left un-tilled stays cooler and retains more moisture.
Photo courtesy of the USDA Natural Resources Conservation Service

Paul Kaiser of Northern California’s Singing Frogs Farm grows fruit and vegetables completely without machinery, a system he refers to as “non-mechanized, no-till.” He said goodbye to his tractor and tiller seven years ago after he felt he was unnecessarily harming wildlife, saw too many machines break down, and watched his soil quality decrease. Now, his eight-acre farm has a robust community supported agriculture (CSA) program, and his soil is full of life.

“I wanted greater productivity and healthier soils with less reliance on machinery,” Kaiser says.

Whereas many farmers believe in breaking up the soil with tractors to control weeds, others, like Kaiser, practice no-till agriculture. A subset of conservation tilling, no-till demands that crops be planted directly into the ground without overturning the earth to ready it for planting. Conservation tilling utilizes the residue (dead crops and plants) from the previous years’ harvest by leaving some, or all, of the residue on the surface before planting.

It took Kaiser two years to make the transition to farming this way, but it has made a big difference during years with lower than average rainfalls such as this one. Kaiser explains, “Our no-till soil management has led to an increase of our soil organic matter (SOM) from 2.3 percent to over 6 percent (at a 12-inch depth). For every 1 percent increase in SOM, an acre of topsoil can hold an additional 16,000 gallons of plant-available water.”

Because the soil retains water, Kaiser is able to use drip irrigation to water his crops for one hour every 5 to 6 days. “And we’re still dry farming tomatoes,” he adds.

The latest estimates say the drought to California could cost the agriculture industry as much as $2.2 billion in losses. And even if rain does come this year or next, scientists predict that global warming will increase the intensity and length of future droughts, making now a good time to begin adapting to a drier, hotter climate. No-till could be an important tool during that adaptation.

The Institute for Atmospheric and Climate Science in Switzerland released a study in July suggesting that no-till farming is beneficial in lowering surface temperatures by as much as 2 degrees Celsius (or nearly 4 degrees Fahrenheit) during summer months. This is important because moderating soil temperatures helps reducing soil moisture evaporation, especially in the top two inches.

According to the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) report from Iowa State University, water filters into soil much faster (at a rate of 5.6 inches per hour compared to 2.6 ) if that soil hasn’t been tilled.